CVE-2022-49595 is a concurrency vulnerability identified in the Linux kernel's TCP networking stack. Specifically, the issue arises from a data race condition involving the sysctl_tcp_probe_threshold variable. This variable is accessed concurrently without proper synchronization, leading to a potential race between reading and writing operations. The vulnerability is rooted in the fact that while the sysctl_tcp_probe_threshold value is being read, it can be changed simultaneously by another thread or process, which can cause inconsistent or unexpected behavior. The Linux kernel patch addresses this by introducing the READ_ONCE() macro to the reader side, ensuring atomic and consistent reads of the variable, thereby eliminating the data race. This fix prevents potential kernel instability or undefined behavior caused by concurrent access to this shared variable. The vulnerability affects specific Linux kernel versions identified by the commit hash 6b58e0a5f32dedb609438bb9c9c82aa6e23381f2 and was published on February 26, 2025. There are no known exploits in the wild at this time, and no CVSS score has been assigned yet.

For European organizations, the impact of this vulnerability primarily concerns the stability and reliability of Linux-based systems, especially those heavily reliant on TCP networking, such as servers, network appliances, and cloud infrastructure. While the vulnerability does not directly imply privilege escalation or remote code execution, the data race could lead to kernel crashes or unpredictable network behavior, potentially causing denial of service (DoS) conditions. This could disrupt critical services, including web hosting, database access, and internal communications. Organizations running Linux kernels with the affected versions in production environments may experience intermittent outages or degraded network performance. Given the widespread use of Linux in European data centers, cloud providers, and enterprise environments, the vulnerability could have a moderate operational impact if exploited or triggered unintentionally. However, the absence of known exploits and the nature of the vulnerability suggest that the risk of targeted attacks exploiting this flaw is currently low.

European organizations should prioritize updating their Linux kernel to the patched version that includes the READ_ONCE() fix for sysctl_tcp_probe_threshold. Kernel updates should be tested in staging environments to ensure compatibility and stability before deployment. Additionally, organizations should implement rigorous kernel monitoring and logging to detect unusual kernel behavior or crashes that might indicate attempts to trigger the race condition. Employing kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR) and Control Flow Integrity (CFI) can further reduce the risk of exploitation. Network segmentation and limiting access to systems running vulnerable kernel versions can minimize exposure. For environments where immediate patching is not feasible, temporarily disabling or restricting access to sysctl interfaces related to TCP parameters may reduce the attack surface. Finally, maintaining an up-to-date inventory of Linux kernel versions in use across the organization will facilitate rapid identification and remediation of vulnerable systems.